# Hidden and Iceberg Orders > Iceberg orders show only part of a large order; hidden orders show none of it. Learn how they work, their priority trade off and how to spot icebergs in the book. Source: https://learn.tradelabsai.com/orders/hidden-and-iceberg-orders/ Track: Orders and Execution · Level: Intermediate · Updated: 2026-10-03 Publisher: TradeLabs AI (https://tradelabsai.com). Education, not financial advice. Cite as: TradeLabs Learn, "Hidden and Iceberg Orders", https://learn.tradelabsai.com/orders/hidden-and-iceberg-orders/ When a large order sits visibly in the order book, other traders can see it and react: they may trade ahead of it, pull their own orders or wait for a better price. Hidden and iceberg orders exist to reduce that information leakage. An **iceberg** order shows only a small part of its full size; a **hidden** order shows nothing at all. Both let larger traders buy or sell without advertising their full intentions. ## Iceberg orders An iceberg order, also called a reserve order, displays a small "tip" in the order book while the rest stays hidden. When the displayed part fills, a new piece of the same size appears at the same price, until the whole order is done. **Example: An iceberg buy order** A fund wants to buy 50,000 shares at $42.10 without scaring sellers. It places an iceberg with a display size of 500 shares. The order book shows only 500 shares bid at $42.10. Each time 500 trade, another 500 appear. Other traders see a bid that keeps refilling but do not see the remaining size behind it. ## Hidden orders A hidden order is a limit order that does not appear in the visible order book at all. It still trades with incoming orders at its price, but nobody sees it waiting. Some exchanges offer hidden orders; dark pools are entire venues built around non displayed liquidity. See [Dark Pools](https://learn.tradelabsai.com/market-structure/dark-pools/). ## The trade off: priority Exchanges usually give priority to displayed orders over hidden ones at the same price. That means: | Order type | Visibility | Priority at the same price | |---|---|---| | Fully displayed limit | Full size visible | Highest, by time | | Iceberg | Only the tip visible | Tip has normal priority; each refill joins the back of the queue | | Hidden | Not visible | Behind displayed orders | So hiding your size costs you queue position. Large traders accept slower fills in exchange for less information leakage. See [Fill Probability and Queue Position](https://learn.tradelabsai.com/orders/queue-position/). ## Spotting icebergs Traders who watch the order book and time and sales sometimes detect icebergs: - **A price that keeps trading but never runs out of size.** Thousands of shares trade at $42.10 while only 500 ever show on the bid. - **Repeated identical displayed sizes** reappearing instantly after fills. - **Volume at a price far above the visible size.** A detected large buyer can act as support, at least until the iceberg is finished. Some order flow traders build strategies around this, though it is far from reliable, since icebergs can be cancelled at any time. See [The Order Book and Market Depth](https://learn.tradelabsai.com/market-structure/the-order-book-and-market-depth/). ## Who uses these orders - **Institutions** buying or selling large positions over hours or days. - **Algorithmic execution systems,** which slice orders into small pieces automatically. See [VWAP, TWAP and POV Execution](https://learn.tradelabsai.com/orders/vwap-twap-and-pov-execution/). - **Active traders** in thinner markets who do not want their size seen. For most retail order sizes, there is little benefit: a few hundred shares in a liquid stock do not move the market or reveal much. ## Icebergs and hidden orders in crypto and futures Several crypto exchanges support iceberg and hidden orders, and futures platforms commonly offer iceberg functionality, sometimes simulated by the trading software rather than the exchange itself. Simulated icebergs are managed by your platform sending new visible orders as each one fills, which means each slice joins the back of the queue. ## Frequently asked questions ### What is an iceberg order? A large limit order that displays only a small portion in the order book, revealing more as each displayed piece fills. ### Are hidden orders legal? Yes. Exchanges offer them, and dark pools are regulated venues for non displayed trading. ### Do hidden orders get filled more slowly? Usually, yes. Displayed orders at the same price typically have priority, so hidden and reserve size fills after visible size. ## Sources - Wikipedia, [Iceberg order](https://en.wikipedia.org/wiki/Iceberg_order) ## Continue learning - Next lesson: [Pegged and Midpoint Orders](https://learn.tradelabsai.com/orders/pegged-and-midpoint-orders/) - Previous lesson: [OTO and OTOCO Orders](https://learn.tradelabsai.com/orders/oto-and-otoco-orders/) - Related: [OTO and OTOCO Orders](https://learn.tradelabsai.com/orders/oto-and-otoco-orders/): OTO orders send a second order only after the first fills; OTOCO adds an OCO pair of exits. Learn how these conditional orders automate a full trade plan. - Related: [The Order Book and Market Depth](https://learn.tradelabsai.com/market-structure/the-order-book-and-market-depth/): The order book lists every waiting buy and sell order by price. Learn to read market depth, what imbalances show, spoofing risks and how depth affects fills. - Related: [Market Impact](https://learn.tradelabsai.com/orders/market-impact/): Market impact is the price movement caused by your own trading. Learn temporary and permanent impact, the square root rule of thumb and how large traders reduce it. - Related: [Fill Probability and Queue Position](https://learn.tradelabsai.com/orders/queue-position/): Your place in the order queue decides whether a limit order fills. Learn how queues work, how to estimate fill probability and why fills can be a warning sign. - Related: [Dark Pools](https://learn.tradelabsai.com/market-structure/dark-pools/): Dark pools are trading venues that do not display orders before trades happen. Learn why they exist, how they work, the concerns about them and how they affect you. - Related: [VWAP, TWAP and POV Execution](https://learn.tradelabsai.com/orders/vwap-twap-and-pov-execution/): VWAP, TWAP and POV algorithms split large orders over time to reduce impact. Learn how each one schedules trades, its strengths and when to use it.